People are giving surprising answers here. But it is really quite simple:

- do you think the company did something wrong?

- do you want to help discourage other companies from doing the same thing in the future?

If the answer is yes to both, then you should testify.

The truth is, no one here has a crystal ball that will tell them the impact of testifying on your future. In life, you sometimes have to just go with what you think it right.